1. Field of the Invention
The present invention is directed to a diaphragm apparatus of a lens that is attached to a single-lens reflex camera, and it also relates to an apparatus for transmitting photometric data on the diaphragm apparatus to the camera body.
2. Description of the Related Art
Usually, single-lens reflex cameras have an automatic diaphragm device in which a diaphragm is fully open in order to provide a bright field of view, the diaphragm being stepped down to a predetermined diaphragm value only immediately before the shutter is released In such an automatic diaphragm device, it is necessary to provide a stopping-down device on the camera body side or the lens side in order to confirm that the predetermined diaphragm value has been effected.